At present, an online Instant Messenger (called “IM” for short) has become a communication tool for most of Netizens which provides terminal services for at least two persons to communicate instant text information, archives, voices and videos on line. The Instant Messenger may realize not only one-to-one information communications between two users but also group communications among multiple users through group establishment. The emergency of groups provides a communication mode of chatting among multiple persons for the Instant Messenger, and a member of a group is able to communication information with multiple other members of the group simultaneously.
A user may create a group through the Instant Messenger, invite as an administrator his friend to join in the group, and add the identifier of the friend such as the number of the friend to the membership list of the group after the friend accepts the invitation. When a user desires to join in a certain group, he may send a message that requests joining in the group to the administrator according to the identifier of the group such as the number of the group, and the identifier of the user will be added to the membership list of the group after the administrator's verification.
However, if a user who desires to invite his friend to join in a group is not the administrator of the group, he has to inform his friend of the identifier of the group, so that his friend can then join in the group through the identifier of the group. In addition, when a user is interested in and desires to join in a group regarding a certain topic such as a group with a topic of travelling, it is possible that a group to which a friend of the user belongs is in accordance with this topic while the friend can not assist the user in adding him automatically into the group. It can be seen that the method for joining in the group in the prior art is not convenient which will make the user's experiences worse.